Means for conserving centrifuged liquids



H. O. LINDGREN Filed July 27, 1926 M VE/II'W? 6 an A a M an: flay/I2 721):

March 19, 1929.

MEANS FOR CONSERVING GENTRIFUGED LIQUIDS w/r/vass: I W

Patented Mar. 19, 1929.

UNITED STATES PATENT OFFICE.

HANS OLOF LINDGREN, OF STOOKHOLM, SWEDEN, ASSIGNOR TO THE DE LAVAL SEPA- RATOB COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

MEANS FOR CONSEBVING GENTBIFUGED LIQUIDS.

Application filed July 27, 1926, Serial No. 125,315, and in Sweden July 29, 1925.

In the operation of centrifugal separators and purifiers'the liquid or liquids are usually discharged from the centrifuge into a surrounding collecting vessel or vessels in a finely divided state. The rapidly rotating separator bowl causes strong air currents in the collecting vessels. If these vessels are in open or restricted connection with the atmosphere, more or less air will flow into and out of the collecting vessels, and the air escaping from the collecting vessels into the atmosphere will carr with it more or less of the finely divided liquid. If the liquid discharged from the separator is so volatile as to be partly or 1 wholly converted into a vapor, the air will carry more or less of this vapor into the atmosphere. If the finely divided liquid or vapor is oxidizable, it may combine with the oxygen of the air, and not only will some of the reaction product escape into the atmosphere, but there may be some danger of an explosion. For example, in the purification and separation of crude oil containing gasoline, the gasoline may in part evaporate, and the air currents will not only carr oil evaporated gasoline, but will entrain with it finely divided particles of the liquid gasoline and if the air be present in sufficiently large roportion it may combine with gasoline to orm an explosive mixture. Thus there results a substantial loss of gasoline and the formation of objectionable reaction products, with danger, in some cases, of explosion.

It is theoretically possible to prevent loss of finely divided liquid and vapor by preventing the admission of air to, and the discharge of air from, the collecting vessels. It is diflicult, however, to maintain the collecting vessels air-tight with respect to each other and to. 4 maintain the lower collecting vessel air-tight with respect to the frame in which the se arator is erected, although means for so oing have been proposed. The difiiculty in providing the necessary air-tight conditions arises from the fact that the rotating separating bowl produces a superatmospheric pressure in some of these chambers, so that gases escape through fissures through which there would be a negligible gas flow if the pressure in the chambers were that of the atmosphere.

The object of the presentinvention is to effectively prevent the escape of gas and liquid from the collecting vessels, or either of them, even in the absence of absolutely air-tight closures between the collecting vessels and between these vessels and the frame. Devices embodying my invention in preferred forms and adapted to accomplish said object are shown in the accompanying drawings, in which Fig. 1 is a side elevation of an apparatus embodying my invention.

Fig. 2 is a partial view of a modification.

Within the sustaining and enclosing frame 1 of the centrifugal machine is mounted a rotatable centrifugal bowl 2, and supported on the frame are collecting vessels 3 and 4 in communication, respectively, with the heavier liquid discharge, and the lighter liquid discharge, of the separator bowl. Precautions should be taken to prevent unrestricted communication between the collecting vessels, and between each collecting vessel and the surrounding or adj accnt spaces, but air tight constructions are unnecessary due to the maintenance, by means to be described, within the collecting vessels, of a partial vacuum which will exclude outflow of air or gas therefrom.

From the collecting vessels 3 and 4 extend the 4 respective pipes 5 and 6 to the respective receiving tanks 7 and 8. Into the latter flow the separated liquids together with any part of the separated fluid that has vaporized, any air that has been sucked'into the collecting vessels, and any finely divided liquid that is entrained in the air and vapor. The gas space in the tanks 7 and 8 communicate with a pipe 9 leading to an injector 10. The injecting nozzle of the injector is connected, through a pipe 11 (in which is interposed a pum 12) with a tank 13, which contains a suita le li uid that is not miscible with the centrifuged charged into the tanks 7 and 8. Beyond the injector 10 is a lgravity separator 14 communicating, throug Beyond the separator 14 is a pipe 16, which may lead to a suitable discharge, directly or through a condenser 17.

In operating the described apparatus, the injector may rst be operated-to create the desired degree of vacuum in the collecting vessels 3 and i and in the entire system between these vessels and the injector. After the can trifuge is started, the finely divided particles of liquid that escape from the collecting vessels and do not settle in the tanks 7 and 8, and any evaporated fluid, as well as any air that has been sucked into the collecting vessels, all come in contact, at the injector 10, with the substance that has been disa pipe 15, with the tank 13.

collecting vessels.

liquid drawn from the tank 13. The finely divided centrifuged liquid is absorbed in the injected liquid and these liquids will drop, through pipe 15 into tank 13. The air is removed through pipe 16, and, if it contains any condensable vapor, should be passed through a condenser 17, in which the vapor is condensed and separated. The condenser may, of course, be located at some other point in the system, as, for example, back of the injector 10, as shown at 18 in Fig. 2, so that the injecting liquid will operate only on air and finely divided liquids.

In Fig. 1, both collecting vessels 3 and 4 are shown connected with tanks (7 and 8) closed to the atmosphere, so that no air can enter the liquid discharge system except such small amount as "may directly be sucked into the In. the separation of crude oil containing great quantities of liquid emulsion, it is not suitable to connect the lower collecting vessel 3 with a closed tank; but a construction embodying my invention may be used to advantage by giving the pump a greater capacity.

The particular fluid that may be used to best advantage as the injecting fluid will depend on the character of the liquids that are separated in the centrifuge. In many in stances, the purified liquid discharged into the collecting vessel 4: may be used as the injecting fluid, in many cases, water may be injected.

l/Vhere the character of the purified or separated liquids that are discharged from centrifugal purifiers or separators in finely divided form is such thatthey tend to react chemically with air to form an objectionable mixture, as, for example, any oxidizable liquid, it is known to prevent the formation of objectionable mixtures or compounds by displacing the air in the space adjacent the discharge, that is, in the collecting vessels, or in both the collecting vessels and the centrifuge, with a neutral gas that does not tend to react chemically with such liquid. In such Case, the pressure within the liquid discharge system will be preferably, although not necessarily, more or less above atmospheric so to more etfec tively insure against admission of air to the collecting vessels. In any case, the gas discharged through the pipe 16 should be so reconducted to some point in the system as to maintain the desired atmosphere of neutral gas in the collecting Vessels. For example, the pipe 16 may be connected with one or both of the collecting vessels 3 and 4 so as to establish an endless circulation of neutral gas. This is indicated at theleft in Fig. 1, where the pipe 20 in dotted lines represents the described extension of pipe 16.

Other examples of uses to which my improvement is adapted are as follows: When separating f. i. fuel oil, it may be suitable to use an injection liquid f. i. already separated fuel oil. When separating a lubricating oil in a closed system, it may be suitable to use a lubricating oil injection liquid.

Having now fully described my invention, what I claim and desire to protect by Letters Patent is:

l. The combination with a centrifuge of the type wherein a substance subjected to the action of centrifugal force is discharged in fincly divided form, of a collecting vessel into which said centrifugal substance is adapted to be discharged, and means adapted to establish a partial vacuum in said collecting vessel and to separate the finely divided liquid from any gas in which it is entrained.

2. The combination with a centrifuge of the type wherein asubstancesubj ected to the action of centrifugal force is discharged and when so discharged is partly in a finely divided liquid state and partly in the form of vapor, and an apparatus adapted to prevent loss of es the centrifuged substance; said apparatus comprising means to establish a partial Vacuum in the discharge from the centrifuge and to separate the finely divided liquid from gas and means to condense said-vapor.

3. The combination with a centrifuge of the type wherein a substance subjected to the action of centrifugal force is discharged in finely divided form, of a collecting vessel into which said centrifuged substance is adapted to be discharged, and means to establish a flow ing stream of such centrifuged substance from said collecting vessel and prevent loss thereof and separate therefrom any air admixed therewith; said means comprising an injector adapted to forcibly inject a liquid into the flowing stream, thereby creating a partial vacuum along the course of said stream and in said collecting vessel, preventing escape of air from said collecting vessel except along the course of said stream. and absorbing the finely divided centrifuged substance in the injecting liquid.

4. The combination with a centrifuge of the type wherein a substance subjected to the ac- 11 tion of centrifugal force is discharged in fine- 1y divided form, of a collecting vessel into which said centrifuged substance is adapted to be discharged,'and means to establish a flowing stream of such centrifuged substance and separate therefrom any air admixed therewith; said means comprising an injector adapted to inject a liquid into the flowing stream and thereby absorb such part of said substance as may be in a finely divided liquid state and a condenser adapted to condense such part of said substance as may be in the form of vapor.

5. The combination with a centrifuge of the. type wherein a substance subjected to the action of centrifugal force is discharged in finely divided form,'of a collecting vessel into which such centrifuged substance is adapted to be discharged, a receiving tank connect ed with the collecting vessel, means to alflowing gas and thereby absorb any liquid in finely divi'ded form that escapes from the tank with said gas and effect the separation from such liquid of such gas.-

6. The combination with a centrifuge of the type wherein a substance subjected to the action of centrifugal force is discharged in finely divided form, of a collecting vessel into which such centrifuged substance is adapted to be discharged, a receiving tank connected with the collecting vessel, and means to establish a flowing stream of gases from the tank and separate therefrom condensable vapor and entrained centrifuged liquid; said means comprising an injector adapted .to inject liquid into the flowing stream and a condenser: whereby the centrifuged liquid is absorbed in the injected liquid and the condensable vapor is condensed and both separated from any noncondensable gas that leaks into and outflows from the collecting vessel.

7. The combination with a centrifuge of the type wherein a substance subjected to the action of centrifugal force is discharged in finely divided form,-of a collecting vessel into which such centrifuged substance is adapted to be dischar ed, a receiving tank connected with the collecting vessel, a gas outflow conduit from the tank, an injector adapted toinject liquid into said conduit and thereby absorb any liquid in finely divided form that may be entrained in the gas outflowing through said conduit, and a pipe connected with said conduit and adapted to con vey the separated gas to the collecting vessel wherein it is again mixed with the discharging centrifuged substance.

8. In centrifugal purification or separating operations wherein a liquid subjected to the action of centrifugal force is discharged in a finely divided form, the process of preventing loss of said finely divided liquid which comprises providing an outflow from the locus of centrifugation for gas in which said finely divided liquid is entrained and forcibly injecting a liquid into the flowing stream.

of gas thereby maintaining the discharge from the centrifuge under partial vacuum and absorbing the entrained liquid before allowing the gas to escape.

9.. Incentrifugal purification or separating operations wherein a liquid subjected to the action of centrifugal force is discharged in a finely divided form, the process of pre venting loss of the centrifuged substance which comprises outflowing from the locus of centrifugation any forei 11 gas carrying finely divided centrifuged su stance, contacting the said outflowing gas and liquid with another liquid and separating the as from the centrifuged substance by absor ing the centrifuged substance in such other. liquid.

10. In centrifugal purification or separating operations wherein a liquid subjected to the action of centrifugal force is discharged in finely divided form in admixture with gas and vaporized centrifuged substance, which comprises outflowing from the locus of centrifugation the said gas together with any finely divided liquid and vapor carried thereby and separating the centrifuged substance from the gas, said separating operation com prising the condensation of the vapor and the absorption of the finely divided centrifuged liquid in another liquid.

11. In centrifugal purification or separating operations wherein a liquid subjected to the action of centrifugal force is discharged in a finely divided form, the process of preventing loss of the centrifuged substance which comprises outflowing from the locus of centrifugation any foreign gas carrying finely divided centrifuged substance and maintaining a partial vacuum on the centrifuged substance whileat the same time effecting a separation of the centrifuged substance from the gas carried thereby.

12: In centrifugal purification. or separat-.

ing operations wherein a liquid subjected to the action of centrifugal force is discharged in finely divided form in admixture with gas :and vaporized centrifuged substance, which comprises outflowing from the locus of centrifugation the said gas together with any finely divided liquid and vapor carried thereby and maintaining a partial vacuum on the pentrifuged substance while at the same time separating both the finely divided liquid and the vapor from the gas.

13. In centrifugal purification or separating operations wherein a liquid subjected to the action of centrifugal force is discharged in a finely divided form, the process of preventing loss of the centrifuged substance which comprises outflowing from the locus of centrifugation' any foreign gas carrying finely divided centrifuged substance and maintainin a partial vacuum on the centrifuged su stance while at the same time separating the gas from the centrifuged liquid carried thereby by absorbing the finely divided liquid in another liquid.

14:. In centrifugal purification or separating operations wherein a liquid subjected to the actionof centrifugal force is discharged in a finely divided form in admixture with gas and vaporized centrifu ed substance, which comprises outflowing rom the locus of centrifugation the said gas together with any finely divided liquid and vapor carried thereby and maintaining a partial vacuum on the centrifuged substance while at the same time separating the centrifuged substance from the gas by condensin the vapor and absorbing the finely divided centrifuged liquid in another liquid.

15, In centrifugal purification or separating operations wherein a liquid subjected to the action of centrifugal force is discharged in a finely divided form, the process of preventing loss of the centrifuged substance Which comprises outflowing from the locus of centrifugation any foreign gas carrying finely divided centrifuged substance, allowing settlement to separate a part or" the centrifuged li uid from foreign gas carrying the remainder of the centrifuged substance, and. maintaining a partial vacuum on the centrifuged substance While separating the gas from the centrifuged substance carried thereby.

16. In centrifugal purification or separatingoperations wherein a liquid subjected to the action of centrifugal force is discharged in a finelydivided form, the process of preventing loss of the centrifuged substance which comprises outflowing from its locus of centriiugation any foreign gas carrying finely divided centrifuged substance, allow-' ing settlement to separate a part of the centrifuged liquid from foreign gas carrying the remainder-of the centrifuged substance,

and maintaining a partial. vacuum on the centrifuged substance While separating the gas from the centrifuged substance carried thereby by contabting the gas With a liquid adapted to absorb the finely divided centrifuged liquid.

17. The combination With a centrifuge of the type wherein a substance subjected to the action of centrifugal force is discharged in a finely divided form, of a collecting vessel into which the centrifuged substance is adapted to be discharged, a receiving tank communicating With, and adapted to receive the centrifugal substance from, the collect ing vessel, a conduit through which any gas carrying the centrifuged substance in vapor or liquid phase is adapted to escape from the tank, and means to separate from the as any such escaping centrifuged substance that has not been absorbed in the centrifuged substance in the tank.

In testimony of which invention, I have hereunto set my hand, at Stockholm, Sweden. on this 8 day of July, 1926.

HANS OLOF LINDGREN 

